Anvil for attachment to electrode structures of electrical precipitators



Sept. 22, 1953 w. F. HULL 00 ANVIL FOR ATTACHMENT To ELECTRODE STRUCTURES OF ELECTRICAL PRECIPITATORS Filed March 27, 1951 INVENTOR.

Patented Sept. 22, 1953 UNITED: STATES rsrslvr o FncEa j NVIL FOR TO. ELECTRODE.

STRUCTURES TATORS' OF. ELECTRICAL PREQ BI- William EHul'l Lomita, Calif; assignor; to-Western: Precipitation Corporation, Los Angeles;

6 Claims. (Cl.183-7) In general, the present inventicn-is concerned with: a structure'for receivingand'transmi-tting' a. blow; and more: particularly it is concerned: with an anvil for attachment to a structural member, of anyone of a number of conventional shapes/constituting a portion ofaframework or other structure.

As is well known in the electrical precipitation. art, an electrical precipitator comprises one or more sets of opposingelectrodes, each set including one; or more. high tension electrodes and one or-more: low tension or grounded electrodes. The electric field. maintained between the op posing; electrodes is usually in such direction as to: cause the material suspended in the gas stream to bescollectedupon the low tension elec trodes; but as a matter cf'actual practice there isan accumulation of material upon the high tension electrodes also. As: a consequence, it is necessary and; this is usually done b y'rapping or jarringthe electrodes withsome typeof hammer mean-s. These-hammers are adapted to strike a sharp blow against the electrode. assembly to set up sulficientr vibration. that the accumulated material ontheelectrooles is jarred loose; and these hammers may be operated-by pneumatic, me chanical; or electric means; Examples ofpneumatically operated hammers are found in- Pat'- ent. 2,525,325 issued October 10," 1950- to Floyd" 1-1. Viets. andPatent 2,392, 088 issued January l, 1845: to J; H. Hamilton et'al. while a mec-hani cal type rapper is found in Patent 2",340,-l79-=-issued January 25 1944 to H. C. Engelman.

In order to receive the blows delivered by the hammer, it has been conventional practice to attach to the frame of the electrode. Not. only doesthe electrode receive-the blowtoprevent local deformation of the frame'structure at the point ofimpact'oith-e hammer, but the anvil'reiniorcesthe frame to prevent bendthe frame memberandresultant misalignment of the electrodes.

In the past; considerable di-fhculty has been experienced in properly attaching these anvils to the electrode frames. Bolts have in many cases worked loose from the v-ibration to thepoint where the anvil is no longer in firmcontact with the frame but moves with respect thereto so that the rapping action is seriously As a. result of the vibrationthe bolts themselves often fall from: fatigue whenv they are stressed. by the rapping blows. These difficulties have not been overcomeby resorting to welding because the prolonged vibration very often causes. axfailure along the line of weld ing; and. once a crack. starts: it spreadsrapidly.

Hence it becomes a generalobject ofmy'invention to design an anvil which can beattached to theirame member of an electrodeasperiodically to. clean both electrodes 4 sembly" in. a: manner that resists the vibra tic-n setup by the continual hammering to which the, anvil is subjected.

It; is. also an object: of my invention to provide an anvil for an electrodestructure in which the means for fastening. theanviltothe structural member oftheframe-is or such character that it is not subjected 1 tostress'e's from the hammer blowson the anvil.

An anvil constructed according to my invention has a blow receiving body: portion having a: plane surface bearing against a structural member constituting a part of the electrode assembly. The plane ofthis bearing surface is generally perpendicular to the direction in which the hammer blows: areapp'lied; thebodyportionof" theanvil there is an integrally. formed hoolcwvithin which is received a portion 0f? the structural member.. The-parts are. so designed and: proportioned that: as: the

anvil'is moved intoltsfinal position, the part of: the: structural member within the-anvil hook is slightly deformed-,. thus placing. both the an vil: and the structural member: under stress when the anvil is in place. At the other side of the blow receiving-body, theanvilhas an arm which usuallyliesalongv side another portion of the structural'i member and is secured thereto by some tension:v member, as for example a rivet. The-axis ofthis rivet is parallel to the bearing surface and perpendicular to the direction of thehammer blows-so thatthe normaltension in the rivet is: parallel to the bearing surface between theanvil and the structural member.

; The blows: applied by thehammer being transverse: to said direction of tension in the fastening -member, the hammer blowsdo not increase or setup any tension stresses in the rivet or similar tension-member; except stresses of small magnitude-that may result from deformation of the anvil underimpact.

How the above objects and advantages of my invention, as well as others: not particularly reierred'to; are attained-Will be better understood by reference tothe following description and to the. annexedrdrawlngs, in which:

Fig: 1 1s a transverse'section through a structural framemember. of an electrode assembly showing an anvil inside elevation" and constructed according tomyinvention attached to the structural member in position with the-rapping; hammer delivering: a blow to the anvil;

Fig. 2 is 'alsl'milarview showing the anvil in a position during'assembly prior to stressing the structural member and the anvil;

Fig. Sis'a sideelevationof'the anvil alone-as viewed fromthe right of Fig. 1'; v

Figs. 4 and dare-enlarged fragmentary views of portions of Figs. 1 and 2 respectively showing: the engagement between the hook on the At.- one side of anvil and a portion of the structural member to which the anvil is attached.

Fig. 1 shows an anvil l constructed according to my invention and mounted upon a structural member l2, constituting a part of the frame of an electrode assembly, in a position to receive a blow from hammer l4 delivered to the anvil for the purpose of vibrating channel l2. Structural member I2 is here shown in the shape of a channel as being typical of the various structural shapes that may be encountered. The common shapes are an angle, a channel, or an I-beam, but the invention is not necessarily limited to any particular rolled shape since the anvil may be applied equally well to a built up member. Channels and I-beams may be considered as composed of basic elements which are angles. An angle consists of two legs disposed at a right angle, or substantially so, to each other; and it is with this basic arrangement of two sections or parts of the structural member that we are here concerned. For that reason the two parts of the structural member are hereinafter referred generically as legs, even though in a case of a channel or I-beam these parts are commonly and specifically termed flanges or webs.

Anvil l0 includes a body portion I5 against which a blow is delivered by hammer M in the direction shown by arrow l6. Anvil body l5 has a plane surface l8 which is adapted to bear against one face of leg I! of structural member i2. This bearing face at I8 is transverse, and preferably substantially perpendicular to, the direction in which the blows from hammer 14 are delivered. As may be seen particularly from Figs,

1 and 4, the width of bearing surface IS on the anvil body is somewhat less than the width of the opposing face on the structural member, larly at the outer or tip end of leg ll. Consequently, for the full length of anvil Hi the bearing area, that is the area of mutual contact between the anvil body and the structural member,-

is spaced inwardly from the tip end of flange l1.

Formed integrally with anvil body i5 is an open hook which extends for the full length of and along one side of body l5. Hook 20 is open as shown in order to receive the tip end of flange H as shown particularly in Figs. 4 and 5. The hook itself does not bear against the leg of the structural member except for the contact at 22 of the extreme end of the hook against the leg on the side opposite to the side of the leg against which anvil surface 18 bears. The position of engagement at 22 is located outwardly on flange- H from the nearest edge of bearing surface [8, i. e., between the edge 3! of surface i8 and the end of flange ll.

Anvil [0 also includes an integrally formed arm 24 designed to lie along and against web 25 of the structural member. The two legs I! and 25 of the structural member are disposed at right angles relative to each other, and arm 24 of the anvil extends at right angles to bearing surface IS in this embodiment of the anvil. When the anvil is attached to an angle or a channel, arm 24 lies against the outer face of one of the legs of the structural member, as shown in Fig. 1. In the event that the anvil is applied to an I-beam, the configuration of arm 24 may be modified to provide a laterally offset filler, or a separate spacer may be supplied, between the arm and the web of the I-beam, since it may be impractical for the arm to engage the web of the I-beam along its full length.

Arm 24 is secured to leg 25 of the structural particumember by a tension type fastening, such as one or more rivets 26. Rivet 26 is disposed with its long axis parallel to bearing surface [8 so that the tension stresses in the rivet, as will be further explained later, are substantially parallel to the bearing surface. Any other suitable tension member may be used for securing the anvil in place, but a rivet is preferred as it offers less opportunity for mechanical failure.

As may be seen from Fig. 3, leg 24 of the anvil is preferably provided with a plurality of holes 21 each to receive a rivet 26. It has been found advantageous to dispose these holes symmetrically on both sides of but not on center line 28 which is also the center line of hammer I4 and defines the direction along which hammer blows are delivered. The rivet holes are spaced from center line and are located about mid-way between the top and bottom of arm 24 to keep them away from points where the bending is the maximum. Along center line 28 and along the top margin of arm 24 where bending stresses in the anvil are greatest, maximum cross sectional area of the anvil is retained.

It is preferable, although not necessary to reinforce the outer end of arm 24 with a rib as indicated at 30. Under hammer blows anvil l0 acts as a beam with center loading; and the addition of longitudinally extending reinforcing rib 30 increases the cross sectional area of the anvil at the area of greatest tensil stresses.

In manufacturing the anvil, it is preferable to machine bearing surface [8 in order to insure that the surface is flat and that the plane of the surface occupies the proper position with respect to the other component parts of the anvil. The end of hook 20 may or may not be machined as desired; but it has been found preferable at least to grind or similarly finish the portion of the surface of flange l1 against which this hook bears. By grinding the surface along the area of contact 22, not only is a flat surface provided which insures good contact between the hook and the leg of the structural member, but also the thickness of flange I1 is controlled to a uniform and predetermined value. This is important in determining the amount of prestressing applied to the structural member.

The shape of hook 20 and the size of the opening between it and the main portion of anvil body I5 is such, with respect to the thickness of the leg of the structural member received in the hook, that the anvil may be rocked freely in a clockwise direction about the tip of the leg H to a position as shown in Figs. 2 and 5. Up to this point, the anvil moves freely and does not bind on the structural member. When it reaches this position there is an angle A of preferably less than 10 but more than 5 between bearing surface I8 and leg ll of the structural member. From here on it is necessary to apply force to rock the anvil about the outer edge 3| of bearing surfac 18 in order to bring the bearing surface into engagement with the face of leg I I. In so doing hook 211 bears down on the tip of flange I! and the tip is deflected downwardly slightly since the location 22 of the engagement of the hook is outwardly of the outer edge 3| of bearing surface I8. The amount of this deflection or deformation is actually very small and is shown in exaggerated form in Fig. 4 as being the difference between the solid line and the dotted line positions of the under side of flange I1. As a result, an initial loading is placed both on hook 20 and the tip of flange l! which serves to lock the anvil to the structural member and hold these two members together snugly at all times.

Since any undesired components of forces or loads are a minimum at right angles to direction It in which blows are applied, it may be desirable to do some preliminary work on the structural member to obtain exact angularity. The two legs I l and 25 of the structural member with which the parts of the anvil cooperate are preferably brought to a right angle, or slightly less, relative to each other. Many times structural shapes are not rolled with suilicient accuracy to insure that this is true and consequently it is preferable in these cases to work over the structural member in order to bring its parts to a desired angular disposition with respect to each other. Bearing surface It forms a reference surface for the remaining portions of the anvil, and the inner surface of arm 2 which bears against the structural member is formed at a right angle with respect to bearing surface l8. If the included angle between the outside surfaces of legs I! and 25 is exactly a right angle, the parts obviously fit together and the anvil seats properly on the structural member; and the same is true if the angle of the legs is slightly less than a right angle initially since the pull on the tip end of leg I! by the anvil then moves the leg to position. An angle over 90 between the outside faces of legs l1 and 25 is to be avoided as then the anvil does not bear properly on the structural member.

Blows delivered by hammer M are delivered in a direction transverse to the axes of rivets 26. Hence these tension members undergo no significant increase in stress as th blows are delivered; and the anvil bears tightly against the channel at all times, even though rivets 26 should loosen in their holes. Also the rivets are not subjected to significant shear loads since the hammer blows are transmitted in their entirety to the member l2.

From the foregoing discussion it will be apparent that changes in th shape and arrangement of parts may occur to persons skilled in the art without departing from the spirit and scope of my invention; and consequently I wish it understood that the foregoing description is considered to be illustrative of, rather than limitative upon, the appended claims.

I claim:

1. An anvil for a structural member of angular configuration, comprising: a blow receiving body bearing against the structural member over a surface in a plane transverse to the direction of blow delivery; and an integrally formed open hook on one side of the anvil body adapted to receive a portion of the structural member within the hook and deflect said portion slightly when the anvil body bears against the structural member over said surface.

2. An anvil for a structural member having two legs disposed angularly relative to each other, comprising: a blow-receiving body having a sur face bearing against one leg of the structural member, the bearing area being spaced from the tip end of the leg; and an integrally formed hook on one side of the body adapted to receive the tip end of the leg and to bear against the leg on only the side opposite the anvil body and at a position spaced outwardly on the leg from the area in bearing against the anvil body.

' 3. An anvil for a structural member having the proper angular two legs disposed at a right angle relative to each other, comprising: a blow-receiving body having a surface bearing against one leg of the structural member, the bearing area being spaced from the tip end of the leg; an integrally formed hook on one side of the body adapted to receive the tip end of the leg and to bear against the leg on only the side opposite the body and at a position spaced outwardly on the leg from the area in bearing against the body; an integrally formed arm at the other side of the anvil body lying along the other leg of the structural member; and a tension member securing said arm tosaid other leg of the structural member, the tension member being disposed to place tension stresses therein substantially parallel to the bearing surface on the anvil body.

4. A structure for receiving and transmitting a blow, comprising: a structural member having a plurality of legs angularly disposed with respect to one another; a blow-receiving body hearing against one leg of said structural member over a surface transverse to the direction of blow delivery; an arm formed integrally with the body and extending away therefrom at an angle to said bearing surface and parallel to a second leg of the structural member; and means fastening said arm to said second leg of the structural member.

5. A structure for receiving and transmitting a blow, comprising: a structural member having a plurality of legs angularly disposed with respect to one another; a blow-receiving body bearing against one side of one leg of said structural member over a surface transverse to the direction of blow delivery; a hook shaped projection formed integrally with the body and extending along one side thereof to engage said leg on the side opposite to said bearing surface and between said bearing surface and the tip end of the leg; an arm formed integrally with the body and extending away therefrom at an angle to said bear ing surface and parallel to a second leg of the structural member; and means fastening said arm to said second leg of the structural member.

6. A structure for receiving and transmitting a blow, comprising a structural member having a plurality of legs angularly disposed with respect to one another; a blow receiving body bearing against one side of one leg of said structural member over a surface transverse to the direction of blow delivery; a hook shaped projection formed integrally with the body and extending along one side thereof to engage said leg on the side opposite to said bearing surface and between said bearing surface and the tip end of the leg; an arm formed integrally with the body and extending away therefrom at an angle to said bearing surface and parallel to a second leg of the structural member; and tension type fastening the arm to said second leg of the to said bearing surface to avoid tension stresses in said fastening means from delivery of blows to said body.

WILLIAM F. HULL.

References Cited in the file of this patent UNITED STATES PATENTS 

